1. Field of the Invention
The present invention relates to an open type X-ray generating apparatus; and, in particular, to an open type X-ray apparatus making it possible to replace a filament part, which is a consumable, by utilizing vacuum aspiration effected by a pump.
2. Related Background Art
Conventionally known as a technique in such a field is Japanese Patent Application Laid-Open No. HEI 10-503618. In the X-ray generating apparatus disclosed in the above-mentioned publication, electron beams emitted from a cathode are focused onto a target by an electromagnetic action of a coil, whereby an X-ray beam is emitted from a target toward an object to be inspected. Here, since the X-ray generating apparatus operates at a very high voltage of 160 kV, it has a separate, large-size, high-voltage power unit which is connected to the X-ray generating apparatus by a high-tension cable.
Since the high-voltage power unit for driving the X-ray generating apparatus has a structure for generating a very high voltage of 100 kV to 300 kV, however, the high-tension cable for transmitting this voltage to the X-ray generating apparatus must become very thick (e.g., a diameter of 40 mm) and heavy. The handling of such a high-tension cable is required to be managed quite strictly. Namely, the degree of freedom in bending this high-tension cable is very low because of its high-tension characteristics and structure, whereby extreme caution must be taken to prevent disasters from occurring due to electric leakage upon connection to the X-ray generating apparatus, and periodical maintenance is necessary for preventing electric leakage from occurring from a connecting part, thus putting an excessive load on operators and users. In addition, the weight of high-tension cable has been a factor further enhancing the burden of operators.
While Japanese Patent Application Laid-Open No. SHO 58-14499 discloses an X-ray generating apparatus having a high-voltage power unit molded with epoxy resin, this X-ray generating apparatus is of a sealed type, which differs from apparatus of a type making it possible to replace a filament by arbitrarily producing a vacuum by utilizing a pump. Also, as measures against discharge at connecting parts from the mold portion to the grid, a bushing made of synthetic rubber is attached thereto. Further, power is supplied to the filament separately from the outside.
For overcoming the problem mentioned above, it is an object of the present invention, in particular, to provide an open type X-ray generating apparatus of a type making its filament part replaceable, whose handling is improved.
The open type X-ray generating apparatus in accordance with the present invention comprises a tubular portion having an electron path, the inside of said tubular portion being vacuumed by a pump; a mold power unit secured to a proximal end side of said tubular portion, the mold power unit having a high-voltage generating part and connecting lines electrically connected to the high-voltage generating part which are enclosed with a electrical insulating mold therein; a target provided in said tubular portion; an electron gun mounted to the mold power unit so as to electrically connect the connecting lines of the mold power unit and opposed to said target with the electron path interposed therebetween.
It is further object of the present invention to provide an open type X-ray generating apparatus comprising; a tubular portion, adapted to be vacuumed by a pump, having a coil part therewithin and an electron path surrounded by the coil part; a target provided in; a mold power unit, secured to a proximal end side of said tubular portion, having a high-voltage generating part and grid and filament connecting lines electrically connected to said high-voltage generating part which are enclosed within a resin mold; and an electron gun having a replaceable filament part electrically connected thereto by way of the filament connecting line and a grid part, electrically connected to the grid connecting line, surrounding the filament part, the electron gun being attached to the mold power unit so as to oppose the target with the electron path interposed therebetween.
This open type X-ray generating apparatus utilizes vacuum aspiration effected by the pump, so as to make it possible to replace the filament part, which is a consumable, thereby improving the maintenance. Such an apparatus is required to have not only durability but also easiness in handling. Hence, for eliminating the high-tension cable in order to improve the handling, a mold power unit in which a high-voltage generating part, a grid connecting line, and a filament line which attain a high voltage (e.g., 160 kV) are molded with a resin is employed, whereas this mold power unit is secured to the proximal end side of the tubular portion, whereby an apparatus of a type integrated with a power supply is realized. Since the high-voltage generating part, grid connecting line, and filament connecting line are confined within the resin mold as such, the degree of freedom in configuration of the high-voltage generating portion and the degree of freedom in bending lines within the mold improve remarkably. Also, since the conventional necessity for the high-tension cable is eliminated, the mold power unit can further reduce its size, whereby the apparatus itself can be made smaller, which remarkably improves the handling of apparatus together with the fact that the high-voltage portion as a whole is enclosed within a resin.